The present invention relates to the art of braiding machines and, more particularly, to an improved arrangement for supporting and transporting strand eyelet tubes along a sinuous path about a braiding axis.
Braiding machines are of course well known and are used, for example, to braid strands of materials such as steel, stainless steel, bronze, polyester, nylon, arramed, carbon fibers, and the like around a tubular substrate such as a flexible tube in connection with producing high pressure hydraulic or other types of pressure resisting hose. The braiding machines can also be used to braid many other products such as sewing threads, sutures, fishing line, ropes of many types, fashion textiles, cables for electrical and electronic use, lifting cables, and many other such products.
One type of braiding machine used for producing products of the foregoing character is known as a maypole or horn gear type braider such as that shown in U.S. Pat. No. 3,783,736 to Richardson, the disclosure of which is hereby incorporated herein by reference for background purposes. In machines of the latter type, bobbin or strand carriers are moved by horn gears or notched rotors along sinuous paths around the braiding point or axis. Adjacent ones of the rotors rotate in opposite directions, whereby half of the carriers move along a sinuous path in one direction about the braiding axis while the other half of the carriers move along a sinuous path in the opposite direction. Each path runs radially inwardly and outwardly of the braiding axis and the two paths cross one another at each alternating direction, whereby the strands leaving the bobbins are interwoven as they converge to the braiding point. Such horn gear type braiding machines are limited in speed due to structural complexity and sliding friction between the component parts thereof and are subject to frequent and costly maintenance as a result of the number and structural interrelationship between the component parts. Moreover, machines of this type are structurally complex and require a high level of precision with respect to the manufacturing of the parts and the obtaining and maintaining of alignment and other structural interrelationships therebetween, whereby manufacturing costs are undesirably high as are the time and expense of maintenance required to maintain the high level of precision. Moreover, the restricted braiding speed reduces production rate and, thus, increases the cost of production.
Another type of braiding machine used for the production of products of the foregoing character is a rotary braiding machine such as that shown in my U.S. Pat. No. 4,275,638 issued Jun. 30, 1981 and the disclosure of which is hereby incorporated herein by reference for background purposes. In a machine of the rotary type, there are axially spaced sets of inner and outer bobbin carriers which are rotated about the braiding point or axis in opposite directions, and a set of strand deflectors located between the carrier sets which cause the strands from one of the carrier sets to cross the path of the other, thus interweaving the strands. In my aforementioned patent, the strands from one set of bobbin carriers are guided axially past the other set of bobbin carriers by individual elongated eyelet tubes which are supported axially between the two carrier sets and driven along a sinuous path about the braiding point and across the path of the strands of the other set of bobbin carriers to achieve the interweaving of the strands about the braiding axis. The eyelet tubes have three axially spaced apart support points adjacent one end thereof, whereby undesirable forces can be imposed on the eyelet tubes during the driving thereof along the sinuous path about the braiding axis. Accordingly, manufacturing precision is required in an effort to minimize the imposition of such forces while, at the same time, providing the necessary stability with respect to supporting the eyelet tubes as they are driven along the sinuous path about the braiding axis. Moreover, even with such control in connection with manufacturing the component parts, braiding speed of the machine is restricted. The forces imposed on the eyelet tube and other component parts of the drive therefore are both radial and sliding frictional forces. The latter results from parts of the drive arrangement being fixed and sliding displacement of the eyelet tubes relative thereto, and the radial forces can impose bending loads on the eyelet tubes as a result of the three axially spaced points of engagement of the eyelet tubes with the support and drive components. Precision in manufacturing increases both manufacturing and maintenance costs, and restricted braiding speed reduces production rate and, accordingly, increases the cost of production.
The improvement according to the present invention is illustrated and described herein in conjunction with the braiding machine disclosed in my aforementioned patent but, as will become apparent in connection with the disclosure herein, the invention is equally applicable to horn gear type braiding machines.